As rear projection screens of this type, there have conventionally been known those screens composed of a single lenticular lens sheet comprising as a base material a synthetic resin such as polymethyl methacrylate, and those screens composed of such a lenticular lens sheet and other lens sheets. To form images on these rear projection screens, imaging light is projected on the screens by using light sources such as CRTs.
In recent years, projection tubes having small projection apertures, such as liquid crystal projectors and light bulbs came to be used as light sources in place of CRTs. However, the conventional rear projection screens have such a problem that, when images are formed on these screens by the use of projection tubes having small projection apertures, scintillation or speckle is caused on the images.
In order to solve this problem, there have conventionally been proposed a method in which the screens are scanned by using laser light sources (see Japanese Patent Laid-Open Publication No. 173094/1993); a method in which the screens are vibrated (see Reference 1 (J. Opt. Soc. Am., Vol. 66, No. 11, November 1976, "Speckle-free rear-projection screen using two close screens in slow relative motion")); and a method in which large amounts of diffusers are incorporated into lens sheets.